Process of printing indigo coloring-matter.



-UNITED STATES .ON-THER' ASSIGNORSTO BADISGHE ANILIN AFEN-ON-THE-RHINE, GERMANY, A CORPORATION.

PATENT OFFICE.

HENRY STALAY ARTHUR HOLT AND KARL REINKING, or LUDWIGSHAF'ENQ & SODA FABRIK, OF

.e s'ooss s OF PRINTING INDIGO COLORING-MATTER.

Specification of Letters Patent.

Patented July 17,1906.

mum... fil d August 4,1905. Serial No. 272,764.

To all whom it may concern:

Be it known that we, HENRY STALAY An- I THUR HOLT, a subject of the King of En land,

and KARL REINKING, a subject of the I rince Regent of Brunswick, doctors of philosophy and chemists, residing at Ludwigshafen-onthe-Rhine, in the Kingdom of Bavaria, German Empire, have invented new and useful Improvements in Processes of Printing Indigo Coloring-hiattergbf which the following is a specification.

The 'method hitherto almost exclusively employed for printing indigo on vegetable fiber is the following: The material to be rinted with indigo is first padded with a soution of glucose and thenis printed with a strongl -alkaline paste which contains indigo. The material thus treated is then dried and afterward subjected for a short time to the action of steam free from air and is washed to develop the color.

We have discovered that maltose can be used instead of glucose and that the'whole process is thereby considerably cheapened. The maltose used may be the unpurified product, or" it may be used in the condition of a solution. The matters which it is'preferred to use, on account of their cheapness,

are the solutions which can be obtained by treatin starch paste with extract of malt or with ot er matter which contains diastase. It is not necessary to make use of pure starch in the reparation of such solutions. When such so utlons are used, good'results are obtained, which'are fully as good as those obtained when a glucose solution of the same specific gravity is employed, and although maltose is regarded as possessing only twothirds of the reducing power of glucose wehave found that less'is needed in our process than if glucose'be used.

The following example illustrates a method of preparing a solution of maltose suitable for use according to our invention; but our invention is not limited to the use of this particular preparation. The parts are by weight. Boil one hundred (100) parts of wheat-starch with water to a'paste and while at a temperature of from sixty to seventy de-- grees centigrade (60 to 70 C.) add two (2) partsof diastafor or a corresponding quan-' tity of malt extract and maintain the mass at this temperature until no more starch re- I mains'unconverted. The time generally required is about from three to four hours. -When the reaction is complete, (which is shown by the solution giving no blue coloration with iodin,) bring the solution to a specific gravit of 1.052 and pad the material with it. T e printing and subsequent operations mfiy be such as are used when a solution of glucose has been employed. They may,

for instance, be such as are employed in Schliepers glucose process. In this exam- 

